tracing/probe: reverse arguments to list_add

Elsewhere in the file, the function trace_kprobe_has_same_kprobe uses
a trace_probe_event.probes object as the second argument of
list_for_each_entry, ie as a list head, while the list_for_each_entry
iterates over the list fields of the trace_probe structures, making
them the list elements.  So, exchange the arguments on the list_add
call to put the list head in the second argument.

Since both list_head structures were just initialized, this problem
did not cause any loss of information.

Link: https://lkml.kernel.org/r/1588879808-24488-1-git-send-email-Julia.Lawall@inria.fr

Fixes: 60d53e2c3b ("tracing/probe: Split trace_event related data from trace_probe")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace_probe.c

@@ -1006,7 +1006,7 @@ int trace_probe_init(struct trace_probe *tp, const char *event,
 	INIT_LIST_HEAD(&tp->event->class.fields);
 	INIT_LIST_HEAD(&tp->event->probes);
 	INIT_LIST_HEAD(&tp->list);
-	list_add(&tp->event->probes, &tp->list);
+	list_add(&tp->list, &tp->event->probes);
 
 	call = trace_probe_event_call(tp);
 	call->class = &tp->event->class;